A method of fabricating a metal silicide layer over a substrate is provided. First, a hard mask layer is formed over a gate formed on a substrate and a portion of the substrate is exposed. Thereafter, a first metal silicide layer, which is a cobalt silicide or a titanium silicide layer, is formed on the exposed substrate. After that, the hard mask layer is removed and a second metal silicide layer is formed over the gate, wherein a material of the second metal silicide layer is selected from a group consisting of nickel silicide, platinum silicide, palladium silicide and nickel alloy. Since different metal silicide layers are formed on the substrate and the gate, the problem of having a high resistance in lines with a narrow line width and the problem of nickel silicide forming spikes and pipelines in the source region and the drain region are improved.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of fabricating a metal silicide layer, comprising the steps of: providing a substrate having at least a gate thereon, the gate having a dielectric and a polysilicon; forming a hard mask layer over the gate but exposes the substrate; forming a first metal silicide layer on the exposed substrate, wherein the first metal silicide layer is a cobalt silicide layer or a titanium silicide layer; removing the hard mask layer to expose the gate; and forming a second metal silicide layer on the exposed gate to form a multi-layer gate structure having at least the dielectric, the polysilicon and the second metal silicide layer, wherein the second metal silicide layer is selected from a group consisting of nickel silicide, platinum silicide, palladium silicide and nickel alloy silicide.
2. The method of claim 1 , wherein the step of forming the second metal silicide layer comprises: depositing a second metallic material over the substrate to form a second metallic layer, wherein the second metallic material is selected from a group consisting of nickel, platinum and palladium; performing a low-temperature rapid thermal process; and removing an unreacted second metallic layer.
3. The method of claim 2 , wherein the low-temperature rapid deposition process is performed at a temperature below 500° C.
4. The method of claim 1 , wherein the step of forming the first metal silicide layer comprises: depositing a first metallic material over the substrate to form a first metallic layer, wherein the first metallic material is cobalt or titanium; performing a first rapid thermal process; removing an unreacted first metallic layer; and performing a second rapid thermal process.
5. The method of claim 4 , wherein the first and the second rapid thermal processes are performed at a temperature between 700° C. to 900° C.
6. The method of claim 1 , wherein the hard mask layer comprises a silicon oxynitride layer.
7. A method of fabricating a metal silicide layer over a substrate having a polysilicon portion and a doped monocrystalline silicon portion, comprising the steps of: forming a hard mask layer over the polysilicon portion of the substrate to expose the doped monocrystalline silicon portion; forming a first metal silicide layer over the exposed doped monocrystalline silicon portion, wherein the first metal silicide layer is a cobalt silicide layer or a titanium silicide layer; removing the hard mask layer; and forming a second metal silicide layer over the polysilicon portion, wherein the second metal silicide layer is fabricated using a material selected from a group consisting of nickel silicide, platinum silicide, palladium silicide and nickel alloy silicide.
8. The method of claim 7 , wherein the step of forming the second metal silicide layer comprises: depositing a second metallic material over the substrate to form a second metallic layer, wherein the second metallic material is selected from a group consisting of nickel, platinum and palladium; performing a low-temperature rapid thermal process; and removing an unreacted second metallic layer.
9. The method of claim 8 , wherein the low-temperature rapid deposition process is performed at a temperature below 500° C.
10. The method of claim 7 , wherein the step of forming the first metal silicide layer comprises: depositing a first metallic material over the substrate to form a first metallic layer, wherein the first metallic material is cobalt or titanium; performing a first rapid thermal process; removing an unreacted first metallic layer; and performing a second rapid thermal process.
11. The method of claim 10 , wherein the first and the second rapid thermal processes are performed at a temperature between 700° C. to 900° C.
12. The method of claim 7 , wherein the hard mask layer comprises a silicon oxynitride layer.
13. A method of fabricating a metal silicide layer, comprising the steps of: providing a substrate having at least a gate thereon, the gate having a dielectric and a polysilicon, wherein the gate is patterned by a hard mask layer and the hard mask layer is on the gate to expose the substrate; forming a first metal silicide layer on the exposed substrate, wherein the first metal silicide layer is a cobalt silicide layer or a titanium silicide layer; removing the hard mask layer to expose the gate; and forming a second metal silicide layer on the exposed gate to form a multi-layer gate structure having at least the dielectric, the polysilicon and the second metal silicide layer, wherein the second metal silicide layer is selected from a group consisting of nickel silicide, platinum silicide, palladium silicide and nickel alloy silicide.
14. The method of claim 13 , wherein the step of forming the second metal silicide layer comprises: depositing a second metallic material over the substrate to form a second metallic layer, wherein the second metallic material is selected from a group consisting of nickel, platinum and palladium; performing a low-temperature rapid thermal process; and removing an unreacted second metallic layer.
15. The method of claim 14 , wherein the low-temperature rapid deposition process is performed at a temperature below 500°C.
16. The method of claim 13 , wherein the step of forming the first metal silicide layer comprises: depositing a first metallic material over the substrate to form a first metallic layer, wherein the first metallic material is cobalt or titanium; performing a first rapid thermal process; removing an unreacted first metallic layer; and performing a second rapid thermal process.
17. The method of claim 16 , wherein the first and the second rapid thermal processes are performed at a temperature between 700°C to 900°C.
18. The method of claim 13 , wherein the hard mask layer comprises a silicon oxynitride layer.
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January 11, 2005
June 12, 2007
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